Powered By
Continue with Facebook
Continue with your email
Cancer that starts in breast tissue doesn’t always stay there. When breast cancer cells metastasize (spread beyond the original breast tumor) and form tumors in other parts of the body, it’s called metastatic breast cancer or stage 4 breast cancer. (Cancer stages are sometimes written in Roman numerals — in this case, stage IV.)
Triple-negative breast cancer (TNBC) is more likely to metastasize and lead to death than other breast cancer subtypes. In metastatic TNBC, the cancer’s spread throughout the body, not the original tumor, is usually the cause of serious complications and death.
TNBC is characterized by its unique molecular profile, fast growth, and distinct patterns of spread. It’s called “triple-negative” because, unlike other types of breast cancer, the cancer cells lack two hormone receptors and one growth-related protein:
These proteins are often used as targets in treating other types of breast cancer. Since they’re missing in TNBC, common hormone therapies and HER2-targeted treatments don’t work. However, newer options are available for some people. For example, the immunotherapy pembrolizumab (Keytruda), used alongside chemotherapy, may help treat metastatic TNBC if the tumor has a protein called PD-L1.
Because TNBC tends to grow quickly and lacks targeted treatments, it’s often linked to a poor prognosis (outlook). Once breast cancer cells spread to other parts of the body — known as distant metastasis — survival rates decrease. According to the American Cancer Society, the five-year relative survival rate — the percentage of people still alive five years after diagnosis — for people diagnosed with metastatic TNBC from 2015 to 2021 is about 15 percent.
Individual prognosis depends partly on where the metastases (distant tumors) develop. In this article, we’ll cover areas of the body TNBC commonly spreads to, symptoms to watch for, and ways metastasis can affect outcomes. Your oncologist (cancer specialist) can help you better understand your specific diagnosis and treatment options.
TNBC commonly spreads to the liver. While liver metastasis doesn’t always cause symptoms at first, it can lead to health problems such as:
To check for liver metastases, your doctor may order blood tests called liver function tests that show how well your liver is working. They might also use imaging scans or perform a biopsy, which involves taking a tissue sample to look for cancer cells under a microscope.
A study in Taiwan looked at overall survival rates in people with TNBC who had metastases in different organs. The researchers measured median survival — the amount of time after diagnosis when half the people in the group were still alive. When cancer spread to the liver first, the median survival was 8.9 months, with a range of 3.5 to 14.4 months.
In some cases of metastatic TNBC, the cancer can spread to the bones. This is more common in older adults with TNBC than in younger people. Bone metastasis doesn’t always cause problems, but it can lead to symptoms such as:
Bone metastasis can also lead to hypercalcemia (high calcium levels in the blood). Hypercalcemia can cause problems like:
To check if your cancer has spread to the bones, your doctor may order imaging tests like X-rays or bone scans to look for lesions (damaged areas) in the bones. A biopsy may also be done.
Compared to other subtypes of breast cancer, TNBC is more likely to spread to other organs like the liver or lungs than to the bones. However, bone metastasis can still happen and affect a person’s chance of survival. In the Taiwan study, cancer spread to the bone first in about 23 percent of participants. For these people, median survival was 16.3 months (ranging from 11.7 to 20.8 months).
The lungs are another common site of metastasis. TNBC may spread to the pleura — the thin layer of tissue that surrounds the lungs. Lung and pleural metastases often occur together, causing symptoms such as:
Cancer in the pleura can also cause a pleural effusion — fluid buildup between the two layers of the pleura. Pleural effusion can make it harder to breathe and may be linked to a worse prognosis.
The researchers in Taiwan found that people whose TNBC first spread to the lungs had a median survival of 16.6 months (ranging from 10.3 to 22.9 months). For those whose cancer first spread to the pleura, the median survival was shorter — 7.5 months (ranging from 2.8 to 12.3 months).
The risk of brain metastasis is a serious concern for people with TNBC. Compared to other types of breast cancer, TNBC is more likely to spread to the brain. Breast cancer brain metastases can cause a wide range of neurological symptoms, depending on the tumors’ location. Symptoms may include:
It can be challenging to treat brain metastases in TNBC, and they can significantly reduce a person’s chance of survival. In the Taiwanese study, people whose cancer first spread to the brain had a median survival of 4.3 months (ranging from 0.6 to eight months) — the lowest among all the metastatic sites studied.
If you find out your TNBC has spread, your oncologist can help you understand your treatment options. Their recommended approach may depend on factors such as your medical history and whether your cancer has genetic mutations (changes).
If you’re just starting cancer treatment, your healthcare provider may recommend chemotherapy as a first step. Although chemotherapy can destroy breast cancer cells, TNBC doesn’t always respond well — and even when it does, the cancer can sometimes return.
If you’ve already tried chemotherapy or your cancer cells have certain proteins, your doctor may try another type of treatment. One option is immunotherapy, which works by helping your immune system recognize and attack cancer cells. Some of these therapies use monoclonal antibodies — lab-made proteins designed to target specific proteins on the surface of cancer cells.
For example, sacituzumab-govitecan-hziy (Trodelvy) combines a monoclonal antibody with a drug that targets a protein called trophoblast cell-surface antigen 2 (TROP2) found on many TNBC cells. The antibody binds to the cancer cell and delivers the drug directly into it, damaging the cell’s DNA and causing it to die. The drug is approved to treat people with advanced or metastatic TNBC who can’t have surgery (like lumpectomy or mastectomy) and have already tried at least two other therapies.
For cancers with mutations in the BRCA1 or BRCA2 genes, a class of drugs called poly (ADP-ribose) polymerase (PARP) inhibitors may be effective. PARP inhibitors, such as olaparib (Lynparza) and talazoparib (Talzenna), can keep cancer cells from repairing themselves after being damaged by chemotherapy.
Even with available therapies, TNBC can be hard to treat. Breast cancer research and clinical trials continue to explore new therapies to improve survival and quality of life.
When you’re living with metastatic TNBC, it’s important to keep in touch with your cancer care team and let them know about any symptoms or side effects you’re experiencing. There are ways to manage these issues and feel better. Your comfort and well-being matter.
On MyBCTeam, people share their experiences with breast cancer, get advice, and find support from others who understand.
Do you have a metastatic triple-negative breast cancer diagnosis? Let others know in a comment below.
Get updates directly to your inbox.
Continue with Facebook
Continue with your email
Become a member to get even more
Join
A MyBCTeam Subscriber
Thank you for this well-written article that explains things in simple language. When in shock over leaving of a family members
We'd love to hear from you! Please share your name and email to post and read comments.
You'll also get the latest articles directly to your inbox.